1. Field of the Invention
The present invention relates to an apparatus for a polishing process, and more particularly, to an apparatus for automatically cleaning a slurry tank.
2. Description of the Related Art
Unevenness of wafer surface is a serious problem, due to the high-integration and multiple layer structure of the circuit distribution of semiconductor devices. Therefore, in order to planarize or flatten uneven wafer surface, chemical-mechanical polishing (CMP) techniques are commonly used.
Cleaning slurry tanks is important for effective CMP. Variables such as slurry residue, dregs, dirty particles, and so on, greatly affect uniformity. These also seriously affect the pH of the slurry and its ion concentration, thereby decreasing manufacturing yield.
Conventionally, slurry tanks are cleaned by hand. However, it is difficult, messy, and ineffective to clean the slurry tank with this method, as well as frequently unsafe.